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New Post: Beginner JigLibX - Sphere Collision to Mesh Collision in this Case?

Spartan2417 — Sat, 23 Feb 2013 14:07:57 GMT

Ive literally had a week of looking a JigLibx for a game project im doing.
At the moment i want to use the engine for collision between my camera and a custom built Maya .fbx. The maya model is of a Cube (6 sides) and on each middle of a side is a square hole, the idea being to allow the camera to go through those holes, but not inside of the cube.

What is the best way of doing this? Im heading towards having a triangle mesh for the cube and having a primitive for the camera but id like to know if this is the best way or theres a better one?

New Post: Vehicle on Network

stark7 — Tue, 15 Jan 2013 01:40:36 GMT

So this might be a late solution response but here it goes anyway. Create a waypoint controller that reads an array of Vector3 which are the waypoints and then only send those from the server to the client. You will need to do a lot more customization but this is probably a very good start.

New Post: rotating Heightmap

stark7 — Mon, 14 Jan 2013 12:35:51 GMT

Hello,

I am looking at the examples inside JiggleGame and I was wondering, is there any way to apply a yaw pitch roll to the heightmap?

One thing that I tried is associating the collisionskin with the body inside the HeightmapObject and then rotating that body with the MoveTo function but that doesn't work.

body.MoveTo(shift, Matrix.CreateRotationZ(0.2f));

body.Immovable = true;

body.EnableBody();

Is there any other way to do this or are we only supposed to work with this horizontally?

This library is fantastic!

New Post: TimeStep per body and negative TimeSteps

pcaston2 — Thu, 13 Dec 2012 16:47:53 GMT

Well I realized that when TimeSpan is negative, objects maintain the same velocities, I will have to look into "fixing" this. Also the collisions seem to only happen on the inside of objects (as if they were inside out) so this might take some work.

Other then that, it's working pretty well. Simply passing a different change in time to each object worked as intended. There was one special case where two objects collided that had the same velocity (Dot product was zero, therefore collision wasn't handled properly). To solve it, I simply scaled the velocity for the dot product calculation by the dilation, which should resolve all collision issues.

I rained some cubes on a 'slow spot' that dilates time around it with falloff. It can be seen here:

http://www.youtube.com/watch?v=JFd1JTdb1gs

New Post: Time Dilation

pcaston2 — Wed, 12 Dec 2012 16:23:28 GMT

I'm trying to change the engine so that each object can process time at a different speed. So far I've created a TimeBody that inherits body, and has an extra parameter called dilation, initially set to 1.0.

Within the PhysicsSystem I am going through Integrate and going to all the functions which pass dt (difference in time) and altering them so they call the functions, for each body, using dt multiplied by the new dilation variable.

The goal is to be able to change the dilation value dynamically, and have the objects work at different speeds relative to each other.

Do you think this could work, or would it take too much tweaking to do in this engine?

Issues I know that might come up are:

What happens when two objects with the same velocity collide as a result of different dilation? (this might work fine)

What happens when a negative dt is passed (I tried passing a negative in before modifications, it seems funky, I'll have to consider using an absolute value and flipping the velocities in these special cases)

Any advice would be great!

My background:

I've got a fair bit of algebra and calculus know-how, built simple 2D engines, this is the first time with a 3D engine, but I have 3D experience so it all makes pretty good sense to me.

New Post: SegmentIntersect collision angle

lordikon — Mon, 13 Feb 2012 14:58:05 GMT

furrie wrote:

Hi,

tanks for the response, but it wasn't needed any more (the thread was created over a year ago)

I figured as much, it was more for anyone else that came across the forums with a similar question.

New Post: SegmentIntersect collision angle

furrie — Mon, 09 Jan 2012 08:40:38 GMT

Hi,

tanks for the response, but it wasn't needed any more (the thread was created over a year ago)

New Post: SegmentIntersect collision angle

lordikon — Mon, 09 Jan 2012 05:29:48 GMT

A segment intersection will return to you a normal vector. Normalize the line segment you used to check for segment intersection, and then do a dot product between your normalized vector and the normal vector you got as a result of the intersection. Then you use acos to change your dotproduct to an angle (in radians).

Vector3 ray = new Vector3(0f, 0f, 0f);
float dist;
CollisionSkin skin;
Vector3 pos, normal;
 
ImmovableSkinPredicate pred = new ImmovableSkinPredicate();
Segment seg = new Segment(ray, Vector3.Down * 1000.0f)
 
world.CollisionSystem.SegmentIntersect(out dist, out skin, out pos, out normal, seg, pred);

// Get the segment you made as a vector
Vector3 segmentVector = ray + (Vector3.Down * 1000.0f);
segmentVector.Normalize();

float dotProduct = segmentVector.Dot(normal);
float angle = (float)Math.Acos(dotProduct);

New Post: Ray<->Heightfield Collision

lordikon — Sun, 08 Jan 2012 05:59:22 GMT

LordIkon wrote:
Ok, next question. If I create a ray, and pass it to JigLibX, is there a feature where it would return to me each thing that ray hit, in order, and the intersection point of each collision?

Also, do rays collide with the insides of shapes, or only the outsides?

Anyone know if JigLibX supports something like this? I don't want to check a line segment against all physics in my scene, I want to cast a line segment and have it return to me all collisions and details about those collisions.

New Post: JigLibX on Windows Phone 7

Cygon — Mon, 23 May 2011 07:37:55 GMT

For your utmost convenience, here's the link: Port to XNA 4.0 and Windows Phone 7.

There also appears to be an XNA 4.0 port in the repository here on CodePlex, but I don't know if it supports Windows Phone 7.

EDIT: Fixed font size. Copy & paste from other CodePlex page causes huge fonts that don't show as such in the WYSIWYG editor :-S

New Post: JigLibX on Windows Phone 7

SomeCallMeTim14 — Mon, 23 May 2011 03:23:19 GMT

JigLibX runs on WP7. I use it in my app RC-AirSim which is on the phone marketplace right now. Take a look under the Issue Tracker tab for the code I used.

New Post: JigLibX on Windows Phone 7

Gruger — Mon, 23 May 2011 02:11:42 GMT

Cygon,

Were you able to port it to Windows Phone 7?

Could you help me do the same?

New Post: SegmentIntersect collision angle

furrie — Thu, 18 Nov 2010 12:28:42 GMT

I'm doing a segmentIntersect, now I want to know the angle at which the angle took place.

New Post: JigLibX on Windows Phone 7

Cygon — Fri, 06 Aug 2010 13:44:22 GMT

Are there any plans porting JigLibX to Windows Phone 7? I gave the current JigLibX release (0.3.1 beta) a try and started providing alternate code paths for the unsafe regions, but once I reached the collision detection code, things got too complicated for a quick afternoon hack ;-)

New Post: question about touching objects

guitargice — Mon, 12 Jul 2010 18:59:04 GMT

Did this issue ever get resolved? I have noticed that the issue does not manifest on larger objects, perhaps this is why only few people have found it. In the case of the original poster, I am assuming his objects were to scale (marbles) which are relatively small. I am getting the same exact issue on the latest version of the code. Just curious if someone has already fixed it.

[Edit]: I managed to get around this problem by scaling down ( * 0.1f ) the "CollToll" variable in the PhysicsSystem.cs file. Worked for me.

New Post: Make Z-axis not used?

davidc14 — Thu, 08 Jul 2010 12:43:52 GMT

This is how I did it, I implemented this code into my character's body class.

Vector3 zPosLock = Position;
zPosLock.Z = 0.0f;
Position = zPosLock;

This code constantly resets the Z position of the character to zero.

Might not be elegant but it's functional.

New Post: Box-Sphere Collision

SZCZUR — Sun, 07 Mar 2010 21:01:24 GMT

i found that is connected with colision direction detection:

i replaced(file:SphereBox.cs ln: ~73)

                if (oldDist < -JiggleMath.Epsilon)
                {
                    dir = oldBoxPoint - oldSphere.Position - oldBoxPoint;
                    JiggleMath.NormalizeSafe(ref dir);
                }
                else if (oldDist > JiggleMath.Epsilon)
                {
                    dir = oldSphere.Position - oldBoxPoint;
                    JiggleMath.NormalizeSafe(ref dir);
                }
                else
                {
                    dir = oldSphere.Position - oldBox.GetCentre();
                    JiggleMath.NormalizeSafe(ref dir);
                }

with:

dir = Vector3.Up;

and now when ball is on top, everything works fine (no jumping) , this dont solve problem because collison with side of bo don't work since it's hardcodet to Vector.Up;

New Post: Vehicle on Network

MateAndor — Wed, 02 Dec 2009 14:15:38 GMT

Hi, i'm Andor Mate!

I have a question with jiglib vehicle. I create networking (Server-Client and i use UDP), but i dont know what datas send in the network.
I try the send the Position and Orientation but its too slow (lagging). After that i try the accelrate and steer, but slow.

Please help me!

Thanks, Andor

New Post: Problems with the car wheels and TriangleMeshObject

gazwik — Mon, 23 Nov 2009 19:32:11 GMT

http://jiglibx.wikidot.com/

http://jiglibx.wikidot.com/forum:start

New Post: Problems with the car wheels and TriangleMeshObject

e66n06 — Mon, 23 Nov 2009 19:28:58 GMT

Latest version.

Where should I have posted?